Processing chamber components, particularly chamber shields, and method of controlling temperature thereof

Abstract

A processing chamber component, for example, a removable chamber shield, that has a tendency to expand when exposed to a heat flux, is temperature controlled. The temperature controlled component is particularly useful where exposed to material deposits during processing by PVD, CVD and etching, for example. The component is provided with temperature control properties that avoid high temperatures and temperature gradients as well as large temperature fluctuations. In the case of a chamber shield, the shield may be formed of a base layer typically of a refractory metal such as stainless steel, which has a relatively low thermal conductivity but is mounted in contact with a heat sink, usually at one end thereof such that its other end, which is free, has a tendency to heat and partially cool from processing cycle to processing cycle. The chamber part is provided with a cladding on the base layer of a material of higher thermal conductivity than that of the base layer. The cladding is preferably a Nobel metal, such as gold, silver or copper, but optimally copper, and is applied across at least one side of the base layer and into thermal contact with the heat sink, and extending to the free end of the part. The cladding layer is at least 0.5 millimeters thick, and typically a thickness of about 1 millimeter is sufficient, and is preferably cold sprayed onto the base layer.

1 . A method of controlling the temperature of a chamber component having a tendency to expand when exposed to heat flux during processing and formed of a base layer having a relatively low thermal conductivity that is in contact with a heat sink at at least one area thereof, the method comprising: 
 cladding the base layer, across a side thereof and into thermal contact with the heat sink, with a layer of relatively high thermal conductivity material that has a higher thermal conductivity than the base layer.    
     
     
         2 . The method of  claim 1  wherein: 
 the cladding includes applying the layer of relatively high thermal conductivity material on a side thereof opposite a side exposed to the heat flux.    
     
     
         3 . The method of  claim 1  where the component is exposed to material deposits during at least one of a physical deposition process, a chemical deposition process, and an etching process, wherein: 
 the cladding includes applying the layer of relatively high thermal conductivity material on a side thereof opposite a side exposed to the material deposits.    
     
     
         4 . The method of  claim 1  wherein: 
 the cladding includes applying the layer of relatively high thermal conductivity copper to the base layer.    
     
     
         5 . The method of  claim 1  wherein: 
 the cladding includes applying to the base layer the layer of the relatively high thermal conductivity material at a thickness of at least approximately 1 millimeter.    
     
     
         6 . The method of  claim 1  wherein the component is a chamber shield and wherein: 
 the cladding includes applying the layer of the relatively high thermal conductivity material to cover a side of the shield facing away from the center of the chamber and extending from the heat sink to a remote end of the shield.    
     
     
         7 . The method of  claim 1  wherein the component is a chamber shield having a base layer formed of stainless steel, and wherein: 
 the cladding includes applying a layer of copper and is applied to a thickness at least approximately 1 millimeter to cover a side thereof facing away from the center of the chamber, extending from the heat sink to a remote end of the shield.    
     
     
         8 . The method of  claim 1  wherein 
 the cladding includes cold spraying the layer of relatively higher thermal conductivity material onto the base layer.    
     
     
         9 . A component for installation in a wafer processing chamber in a location where it is likely to be exposed to heat flux during processes performed in the chamber, the component comprising: 
 a base layer having a relatively low thermal conductivity;    a surface configured for thermal contact with a heat sink of the chamber;    a remote portion thereof remote from the heat sink;    a layer of relatively high thermal conductivity material that has a higher thermal conductivity than the base layer cladding a surface thereof extending from the heat sink to the remote portion.    
     
     
         10 . The component of  claim 9  wherein: 
 the layer of relatively high thermal conductivity material is formed of a Nobel metal.    
     
     
         11 . The component of  claim 9  wherein: 
 the layer of relatively high thermal conductivity material is formed of copper.    
     
     
         12 . The component of  claim 9  wherein: 
 the base layer is formed of stainless steel; and    the layer of relatively high thermal conductivity material is formed of copper.    
     
     
         13 . The component of  claim 9  wherein: 
 the layer of relatively high thermal conductivity material is formed of a Nobel metal at least approximately 0.5 millimeter thick.    
     
     
         14 . The component of  claim 9  wherein: 
 the layer of relatively high thermal conductivity material is formed of copper at least approximately 0.5 millimeter thick.    
     
     
         15 . The component of  claim 9  wherein: 
 the base layer is formed of stainless steel; and    the layer of relatively high thermal conductivity material is formed of copper at least approximately 0.5 millimeter thick.    
     
     
         16 . The component of  claim 9  wherein: 
 the base layer is formed of a refractory metal; and    the layer of relatively high thermal conductivity material is formed of copper at least approximately 0.5 millimeter thick.    
     
     
         17 . A wafer processing apparatus comprising a vacuum chamber having therein the component of  claim 9 .  
     
     
         18 . A chamber shield for installation in a wafer processing chamber to protect walls thereof from deposits of material from processes performed in the chamber, the shield comprising: 
 a hollow cylindrical base layer formed of a refractory metal having an inner surface adapted to enhance adhesion of the material from the processes;    a proximate end of the cylinder being configured for mounting the shield to a wall of the chamber in thermal contact with a heat sink of the chamber;    a remote end of the cylinder being remote from the heat sink; and    a layer of Nobel metal having a higher thermal conductivity than the base layer and cladding the outer surface of the base layer from the proximate end to the remote end.    
     
     
         19 . The shield of  claim 18  wherein: 
 the hollow cylindrical base layer has an inner surface having a twin arc spray coating of aluminum thereon adapted to enhance adhesion of the material from the processes.    
     
     
         20 . The shield of  claim 18  wherein: 
 the layer of Nobel metal is a cold sprayed layer having a purity of approximately 99 percent.    
     
     
         21 . The shield of  claim 18  wherein: 
 the layer of Nobel metal is a copper.    
     
     
         22 . The shield of  claim 18  wherein: 
 the base layer is formed of stainless steel.    
     
     
         23 . A wafer processing apparatus comprising a vacuum chamber having therein the shield of  claim 18.